Treatment of textiles



July 12, 1955 GAUNT ETAL 2,712,683

TREATMENT OF TEXTILES Filed July 17, 1951 ALFRED GAUNT N RMAN KENDALL EAQLE HERBERT JOHN R055 ATTOE NEYS United States Patent Ofiiice 2,712,683 Patented July 12, 1955 TREATMENT OF TEXTILES Alfred Gaunt, Bailey, Norman K. Earle, Brighouse, and Herbert John Ross, Runcorn, England, assignors to T. F. Firth and Sons Limited and Imperial Chemical Industries Limited, both corporations of Great Britain Application July 17, 1951, Serial No. 237,982 Claims priority, application Great Britain July 27, 15ll 8 Claims. (Cl. 28-74) The production of woven fabrics from raw fibre involves many operations. In the case of wool fabrics, the cleansing operation may be carried out at various positions in the sequence; sometimes the material is treated while it is in the yarn form but usually when it is in the woven state. With the exception of the furnishing fabric and carpet trades and possibly the hosiery trade it is unusual to make use of scoured yarns.

In the carpet trade in particular, use is made of yarn spun from fibre which may or may not have been dyed before spinning. When using an undyed fabric, the resulting yarn, being on a spinners package, is reeled into hanks, scoured in an aqueous detergent and/or alkali, dyed, dried and wound into a package convenient for the subsequent weaving process. When using yarns from previously dyed fabric, it is possible and advantageous to utilise the spinners package itself for the subsequent weaving process. The processes of reeling, scouring, dyeing, drying and winding after spinning are thus eliminated and certain specific benefits accrue. Thus the yarn being woven in the greasy state offers less resistance to the withdrawal of the wires in the weaving of carpets and other pile fabrics and the assistance normally required by applied lubrication is unnecessary. In addition the greasy yarn is stronger than scoured hank dyed yarn.

However when greasy fibre is used in the manufacture of carpets, the presence of the oil necessary for spinning increases any tendency to collect dust and dirt, and since the scouring of the woven fabrics is not regarded as practicable, any cleansing has had to be carried out by means of an organic grease solvent. Carpet undergoing this process suifers from the loss of sizing agents which may previously have been applied in some stage of manufacture.

In addition as it is not regarded as practicable to scour the woven carpet such fabrics as are woven from scoured yarn will be left as a consequence with any applied lubrication and the adventitious dust and dirt.

Further in the case of the finished fabrics a degree of stiffness is frequently desired and it is usual to impregnate the materials with a size. This operation is often carried out by passing the textile material over rollers coated with a glue or starchy compound such as farina or a hydrophilic material applied from an aqueous medium and the sizing operation is generally carried out as an independent process designed only to effect this single purpose.

It will be abundantly evident that the above processes are time consuming, expensive to operate and require the use of extensive equipment and of appreciable quantities of heat and power. In addition, there is a wastage of fibre and yarn during processing and a considerable consumption of detergent chemicals and spinning oil and ene etc., chlorinated tate, copolymers of vinyl chloride added lubricants without any practical means of recovery for reuse. Further, in the case of carpets, pile fabrics and the like with which this invention is particularly concerned the finished article is not in the most desirable state. In this connection the carriage of dirt and oil due to the manufacture has been already mentioned. These impurities will obviously be deleterious to the appearance of the fabric, the presence of dust and grit will detract from the wearing qualities and furthermore the presence of oil will, during normal use, tend to increase the collection of more dirt and grit and at the same time render its removal by normal household cleaning more difficult.

We have now found that the above mentioned disadvantages apparent in the steps comprising the complete manufacture of carpets, pile fabrics and the like as well as defects in the finished material can be eliminated in an inexpensive and surprisingly convenient and advantageous manner by combining the processes of oil removal, cleaning and sizing of such materials into one operation. Our process involves the combination of degreasing and cleaning a carpet, pile fabric or like material by means of a volatile grease solvent and thereafter applying to the fabric while still Wetted by the solvent a sizing material which is soluble in the grease solvent. By this process we are enabled not only to eliminate many of the steps and much usage of material hitherto found essential in the manufacture of carpets and the like but to provide means whereby material used in processing can be recovered for reuse and in addition to produce a final product of better appearance and enhanced durability.

For example, the steps which may be eliminated by the process of the invention include hanking of yarn, scouring, drying and winding. Further we are able to achieve the very important advantage that weaving may be effected while the yarn still carries oil added to facilitate spinning.

Accordingly the present invention consists in a step in the process for the manufacture of carpets, pile fabrics and the like which comprises treating the said fabrics with a volatile grease solvent whereby grease and dirt are removed, treating the cleaned fabrics while still wet with solvent with a sizing agent which is soluble in the organic solvent and finally treating the sized fabric to remove the solvent.

In carrying out the process of our invention a large number of organic grease solvents are suitable, including volatile hydrocarbons such as white spirit, benzene, toluhydrocarbons such as trichloroethylene, perchloroethylene, dichloroethylene and carbon tetrachloride, and solvents such as acetone and other ketones and esters etc. However, for many reasons we find that it is advantageous to use a chlorinated hydrocarbon solvent, and in particular trichloroethylene be cause of the high solvent eificiency, non-inflammable nature and suitable physical properties such as convenient boiling point and low latent heat of vaporisation.

As sizing agents a large number of plastic or resinous products may be used either singly or collectively among which may be mentioned chlorinated rubber formulations with or without varying proportions of chlorinated paraffin waxes, modified rosins such as ester gums and zinc calcium resinate, ethyl cellulose, polystyrene, vinyl acewith vinyl acetate, polymerized methyl methacrylate, phenolic resins and the bitumen residues obtained in the refining of petroleum oil.

In the treatment of the fabrics with the sizing agent we are not limited to a particular method of application; we may, for example, apply the agent in the finely divided solid or liquid form, for example as a spray. Alternatively, we may in suitable circumstances apply the size by means of a transfer roller or the like, rotating in a bath of molten sizing agent. More conveniently; however, we use a solution of the sizing agent in an organic solvent and advantageouslythe solvent used is the same as that employed in the degreasing and cleaning step. At this stage in the discussion it should of course be mentioned that the most effective utilisation of the sizing agent in the case of carpets and the like, is only achieved when the agent is applied to the side of the fabric comprising the non-pile portion which side is conveniently referred to'throughout therest of the specification as the back of the fabric and this accordingly provides a further feature of the invention.

It has been further found, in particular in the advantageous form'of the invention in which the sizing agent is applied to the back of the fabric from a solutionthat the most effective use of the size for'imparting the desired 7 physical properties of the carpet and for effective anchoring of pile is obtained when the final removal of the solvent is efiected by drying which should be carried out in a manner involving the application of a heat source to the back of the fabric. 7

There may also be incorporated in the sizing solution insecticidal agents such as dichlorodiphenyltrichloroethane, benzene hexachloride and the like, and antimildew agents such as tetra methyl thiuram disulphide, organic zinc salts such as zinc resinate, or beta-naphthol in alcoholic solution and the deposition of these on the fabric renders them mothproof and mildew proof for a considerable period after treatment. Accordingly, as a further feature of our invention we include combining the treatment of the fabrics with a sizing agent with the proofing of the fabric against attack by insects and other vermin and by fungi. It is sometimes desirable to incorporate various types of adiuvant with the sizing agent and fillers such as china clay, chalk or talc and the like may be readily employed.

;In carrying out the degreasing and cleaning of the fabrics by the process according to the present invention, use is naturally made of the volatile organic grease solvent in its liquid state and in the subsequent discussion we shall exemplify the grease solvent by trichloroethylene and the fabric as a normal carpet having the pile on one'side only. The degreasing and cleaning is most readily effected by running a continuous length of carpet through a volume of the trichloroethylene preferably using a succession of baths provided with overflows in such a manner that a;clean trichloroethylene enters into the bath from which the almost completely degreased carpet leaves, and in which there is, in efiect, a counter-current treatment. In carrying out this process the temperature of the trichloroethylene is-not critical but we do in fact prefer and have indeed found it advantageous to use the trichloroethylene at temperatures not appreciably higher than normal. Likewise the number of successive baths of trichloroethylene is not critical and the only criterion in this stage of the process is that sufiicient treatment should be given to provide for the effective removal ofthe grease and adherent dirt. The impure trichloroethylene flowing from the last bath of the series may of course be readily purified and adapted for reuse by conventional means, such as filtration, evaporation and condensation. There is, however, at this point'the necessity to emphasize an advantage of our present invention in that these steps afford the means for recovering oily spinning and weaving aids for reuse.

On the emergence of the degreased and cleaned carpet fromthe trichloroethylene it is of course fully saturated with trichloroethylene, and indeed in such a condition that trichloroethylene drips from the carpet. It is possible to proceed immediately to the treatment of the carpet with the sizing agent while it is still in this dripping condition. We have, however, found marked disadvantages in attempting so to carry out the process and for the most effective conduct of our process we submitthe carpet to an operation designed to abstract a considerable proportion of the trichloroethylene carried from the degreasing bath. Advantageously, this part of our process is so conducted as to leave a content of trichloroethylene on the carpet hisuiiicient to cause any drain of liquid therefrom. The removal of the extraneous trichloroethylene may be carried out by any suitable method, for example, by vaporisation, by mangling or by an air blow. We have, however, found itrnost satisfactory to suck air through the carpet from the pile to the back. The quantity of trichloroethylene, or indeed any other solvent, which can be carried by the carpet while it is in this advantageous condition for the operation of our process will naturally vary according to the type of carpet or other material being treated. This variation may be within very wide limits but it can be stated that the quantity of trichloroethylene carried by the normal carpet is oftheorder of its own weight. Reference has been made to the amount of trichloroethylene carried from the degrea'sing' bath and to the advantage of adiusting the amount before.

7 treating with a sizing agent as the amount of trichloroethylene on the carpet has a bearing on the application of the sizing agent particularly when the latter is applied as a solution, a method which we prefer. it will be apparent that in no case will it oe possible to guarantee consistently reproducible quality of the finished carpet unless it is possible to guarantee that the amount of size taken up by a unit weight of carpet is consistently maintained with appropriate limiting values. In the present invention we are not limited to a specified weight of sizing agent for a unit weight of carpet as it is essential tobear in mind that different qualities of carpet require ditferent Weights of sizing agent in order that the finished carpet shall exhibit its most desirable qualities. For example, certain qualities of carpet require as littie as 2% of sizing agent whereas others may take 50% or even more sizing agent based on the weight of carpet. The advantage flowing from the step in our process of adjusting the weight of trichloroethylene carried by the carpet wherebythe correct application of the sizing agent is facilitated will therefore now be apparent;

From the above it will be evident that the concentration of the sizing agent solution necessary for satisfactory treatment is not critical depending as it does on the nature and quality of the carpet, the quantity of trichloroethylene it carries and the finish which is required, However, it is inmost instances convenient to use a solutionof sizing agent in as concentrateda form as possible, provided it is not so concentrated as to lead to premature deposition of the sizing agent. v i

As it will be evident thatmany types of finish may be desired and that different sizing agents will give ditferent finishes it will be equally evidentthat selection of the t V sizing agent is not a critical feature of the invention. A number of different materials have already been listed as suitable sizing agents and we have found that they give satisfactory results. i t

We have further found that the 'aforedescribed. process of the invention'may becarried out in an extremely convenient and efficient-manner in an apparatus in which are combined means for successively passing continuous lengths of carpet through one or more compartments containing an organic degreasing solvent,'removing solvent liquid from the carpet, applyinga sizing agent to the back of the carpet and drying involving the application of heat to the back of the carpet. Thus in an ex.- tremely compact and unitary apparatus we are enabled to combine means for processing fabric with the: elimination of a number of separate and'individually controlled pieces of apparatus.

According. to a further feature of our invention therefore an apparatus for the treatment of woven fabrics such as'carpets, pile fabrics and"the:like comprises a.;com-

binatiOn Of means for successively treating continuous lengths of fabric with an organic volatile grease solvent, removing liquid solvent from the fabric, applying sizing agent to the back of the fabric and drying including means for the application of heat to the back of the fabric.

An advantageous form of this further feature of our invention consists in an apparatus for cleaning, degreesing and sizing which comprises a combination of means for cleaning and degreasing strips of woven fabric by an organic solvent, sucking air through the fabric, applying a solution of a sizing agent to the back of the strips of fabric and finally removing the solvent by applying heat to the back of the fabric.

It will of course be appreciated that the apparatus of the invention includes conventional means such as driven rollers, guide rollers and like devices for introducing, guiding and withdrawing fabri into, through and out of the various component parts.

The apparatus of our invention is particularly applicable to the hereinbefore described process for the manufacture of carpets, pile fabrics-and the like.

It will naturally be appreciated that the means comprising the parts of the apparatus according to the invention may in many cases be supplied by more than one form of equipment. For example, the means in which the carpet is treated with solvent may be in a single tank which may or maynot have bafiles and squeeze rollers incorporated or it may be a series of separate tanks; the means for removing extraneous solvent may be a mangle, or a drying chamber or a blast of an inert gas; the means for applying size may be a spray, a transfer roller or even a slot adapted to flow a liquid into contact with the car et; the means for drying may include air drying, steam heated boxes or rotating heated rollers. Thus many different forms of equipment may be combined to co-operate in the apparatus of the invention.

In a preferred form of the apparatus according to our invention, however, the carpet first passes into a cleaning compartment containing a number of wash tanks filled with a volatile organic solvent preferably trichloroethylene. The route of the carpet is so arranged that the material, conveyed by means of a plurality of rollers, is made to enter each wash tank in turn, coming into contact with cleaner solvent as each successive tank is entered. A continuous stream of distilled solvent flows into the last of these wash tanks to be entered by the fabric and the tanks are so arranged adjacent to each other that overflow of solvent takes place successively from the last wash tank to the first, the overflow from the first tank being collected for purification and reuse and for recovery of the dissolved grease, oil, etc.

From the last wash tank the carpet is, if desired passed through a mangle and thence over one or more slotted extraction pipes in such a manner that the back of the carpet makes contact with the slots as it moves transversely across the pipes. A fan is connected to the pipes to causesuction whereby air is drawn through the carpet and the slots to remove extraneous solvent provision being made for the abstracted solvent to be collected with the aid of a cyclone arrangement. The wash tanks, mangle and extraction pipes are all located in a compartment provided with a seal designed to limit the free escape of solvent vapour.

The carpet is next directed over rollers to a sizing device while still wet with the organic solvent. The sizing operation is advantageously performed by employing a transfer roller which rotates on a horizontal axis and is so located that on rotating a part is always submerged in a sizing solution. The carpet is made to proceed over the transfer roller so disposed that sizing solution is transferred to the back of the carpet from the roller as it rotates.

From the sizing roller the carpet is passed to a drying chamber where it is made to traverse a considerable the carpet is passed before leaving the chamber and these connect to an air heater and fan which are externally situated to the drying chamber. The fan serves to drive hot air through the connecting pipe to the air blow boxes so that it passes through the perforations in the air blow boxes and through the carpet in its last stage of drying. The air circuit is completed by a condenser which is located exteriorly of the drying chamber and the exit from the drying chamber to the condenser is located at the lower end of the drying chamber. The organic solvent recovered by this arrangement may conveniently be reused in the wash tanks provided for the cleaning. If desired solvent vapour which may be entrained in the interstices of the carpet leaving the apparatus can be removed and recovered by appropriate means.

The apparatus of this invention will now be mof'e particularly described by reference to the accompanying sectional drawing, not to scale, and by way of exemplifying a process according to the invention reference will be made to a suitable method for the treatment of carpet. In the drawing the individual components of the apparatus are represented diagrammatically and the carpet itself is represented by a broken line 46, the pile surface being indicated by a series of tufts at intervals.

A length of carpet requiring treatment is directed to a cleaning compartment 4 through a lead-in conduit 1 fitted with a guide roller 3 the entrance to the compartment being provided with the seal 2 to obstruct the escape of solvent vapour.

The carpet is moved continuously through a series of wash tanks, 6, 7, 8 and 9 which are kept supplied with a constant flow of trichloroethylene through pipe 5 to tank 9 last entered by the carpet and are so arranged that the overflow from each tank enters the tank directly adjacent to it and counter to the direction of travel of the carpet. Contaminated trichloroethylene finally leaves by overflow pipe 44, from tank 6, which is the one first entered by the dirty carpet. The trichloroethylene is collected for purification and recovery, in means not shown, of clean trichloroethylene and oil for reuse.

The carpet in proceeding through the wash tanks counter-current to the direction of flow of the trichloroethylene enters tank 9 almost completely cleaned and is there brought into contact with the pure solvent. On

the purpose of steering the carpet on the course desired. The carpet is then directed through a mangle 11 which may for certain work be by-passed and thence over a number of extraction pipes 12. The pipes are arranged in parallel and so located that the back of the carpet passes over in transverse fashion each of the pipes. Along the top of each pipe is a slot 45 and each is connected to a fan 15 which sucks air, trichloroethylene vapour and droplets through the duct 14 for delivery to a cyclone arrangement. in the cyclone 16 the air and vapour stream deposits the droplets of trichloroethylene which collect and run into a tank not shown in the diagram through the exit l9. The trichloroethylene thus removed is returned to the cleaning system through pipe 18 leading to wash tank 8. A pipe 17 connects the cyclone directly with the cleaning compartment 4 for return and reuse in the extraction pipes of the air and vapour which has been deprived of the trichloroethylene droplets. it will be noted that in this system the gas circulating in the extraction pipes and cyclone cannot vaporise trichloroethylene from results in the finished each of these air passes over a traverse bar which has the same function as the traverse bar It) to which reference has already been made. The back of the carpet is then brought into contact with a sizing roller 26 which constantly rotates on a horizontal axis and in so doing picks up a quantity of a solution of a sizing agent contained in the vessel 27 V and thereby transfers an appropriate amount to the carpet. '28 indicates the level '27 and this level is maintained constant by appropriate of solution in this containing vessel feed and overflow means not shown. The carpet so moves over the sizing roller that the back'of it only comes into contact with the sizing roller and therefore transfer of the sizing solution is confined to the back of. the carpet.

Still saturated with organic solvent the carpet is directed over rollers through the conduit 30 toa drying chamber 31. A seal 29 can be provided to obstruct flow of solvent vapour between tht sizing compartment and the drying chamber. 1

' On entering the drying chamber 31 the carpet proceeds over the traverse bar 32 and thereafter over a considerable number of steam heated boxes 33. The conditions in the drying chamber are, of course, adjusted to'ensure that the carpet is dried by the time it leaves the exit 37. It must also be noted that in order to achieve desirable carpet the arrangements must be such that heat is always applied to the back of the carpet. Thus a path of reversing direction is arranged to maintain the back at all times in contact with the hot boxes in the drying chamber.

a In a preferred form of apparatus for carrying out the invention a refinement is introducedto assist in the removal of the solvent from the carpet and its recovery for reuse. This consists of two air blow boxes 34 located at the exit of the drying chamber the surfaces of which have a number of perforated holes and these are connectedby inlets 35 to a pipe 38 and thence to an air heater 39 and a fantl. The hot air generated in the air heater 39 is driven by the fan 40 in a continuous stream through the pipe 38 and inlets 35 to the air blow boxes 34. The carpet leaving the last drying box is made to pass over blow boxes 34 and so a constant stream of hot air is constantly. passed from the air blow boxes through the carpet to thechamber 31. The air circulation is completed through an outlet 41 located at the base of the chamber 31 to a condenser 42 and thence through a duct 43 leading to the fan 40. By this means thedual purpose is achieved of freeing the finished carpet from trichloroethylene and providing a continuous stream of hot air passing through the drying chamber 31 to take the vaporised solvent to the condenser 42 where it is con-. densed for return to the cleaning chamber.

It is, of course, obvious that during the operation of the process and apparatus according to our invention interruptions and stoppages may occur due to failure of power, steam or cooling water or other causes. A sudden stoppage can cause serious damage, for example, when a restricted area 'of' fabric is in prolonged contact with a hot surface or with sizing means. Accordingly we provide appropriate safety measures where possible to obviate such risks. As the safety measures are normally conventional and may be numerous and may vary according to circumstances we have not thought it necessary to describe them in detail.

From the above description it will be evident that our process is capable of wide variations in its methodbf operation and that alternative forms are available in the con.- struction of the apparatus but for purposes of illustration and not limitation one method of carrying out the process is described in the following example.

Example Using an apparatus constructed according to the above description a continuous length of an Axminster type can pet in greasy condition 18'' wide and weighing 3% lbs. per sq. yd. was passed through trichloroethylene at room temperature at the rate of 4 yds. per minute thence over extraction slots operating to leave the carpet containing approximately the extraction slots the path of the carpet was over a transfer roller rotating in a solutionof calcium zinc resinate in trichloroethylene. The solution contained 35% by weight of calcium zinc resinate and the carpet was finally dried by passage over steam heated chambers in contact with the back of the carpet. A

The treated carpet was found to be thoroughly clean and bright in colour with the desirable stifiness and good anchorage of the pile. resinate in the'finished carpet was approximately 0.2 lb.

per sq. yd.

In another run under precisely the same conditions and r with a similar carpet a sizing solution containing a phenolic ester gum and a chlorinated rubber of 65% chlorine content in trichloroethylene was used. The composition of the solution by weight was ester gum 25%, chlorinated rubber 5%. The finished carpet exhibited similar qualities to those obtained in the first run and contained in a square yard 0.26 lb. of the mixed sizing agent.

What we claim is:

1. In a process for the manufacture of fabrics comprising a backing and upstanding pile, the yarns making up the fabric comprising an appreciable proportion of wool, the combination of steps comprising treating said fabric comprising wool while in a greasy, unsized condition with a volatile organic grease solvent to remove grease and accompanying dirt, thereafter applying to the thus cleaned fabric while it is still wet with solvent a sizing agent which is soluble in the organic solvent and finally removing the solvent from the sized fabric.

2. A process as recited in claim 1, in which the sizing agent is applied to the back of the cleaned fabric.

3. A process as recited in claim 1, in which the sizing agent is supplied to the cleaned fabric as a solution of the size in the same solvent used in the degreasing and cleaning .step.,

4. A process as recited in claim 1, in which thesolvent content of the cleaned fabric is adjusted to the desired value by application of a suction to the back of the fabric immediately prior to the application of the sizing agent.

is a chlorinated hydrocarbon. V 6. A process as recited in claim 5, in which the solvent is trichloroethylene. 7. The process as recited in claim 1, wherein a pesticide and fungicide are applied to the 'fabric'with the References Cited in the file of this patent UNITED STATES PATENTS 1,943,000 Chandler Jan. 9, 1934 2,219,728 Strube Get. 29, 1940 its own weight of trichloroethylene. From The content of calcium zinc 5. A process as recited in claim 1, in which the solvent 

1. IN A PROCESS FOR THE MANUFACTURE OF FABRICS COMPRISING A BACKING AND UPSTANDING PILE, THE YARNS MAKING UP THE FABRIC COMPRISING AN APPRECIABLE PROPORTION OF WOOL, THE COMBINATION OF STEPS COMPRISING TREATING SAID FABRIC COMPRISING WOOL WHILE IN A GREASY, UNSIZED CONDITION WITH A VOLATILE ORGANIC GREASE SOLVENT TO REMOVE GREASE AND ACCOMPANYING DIRT, THEREAFTER APPLYING TO THE THUS CLEANED FABRIC WHILE IT IS STILL WET WITH SOLVENT A SIZING AGENT WHICH IS SOLUBLE IN THE ORGANIC SOLVENT AND FINALLY REMOVING THE SOLVENT FROM THE SIZED FABRIC. 